Single-phase commutator-motor.



No. 891,784. PATENTED JUNE 23,1908.

. 's; s. SEYPERT.

SINGLE PHASE GOMMUTAVTOR MOTOR.

APPLICATION FILED JAN. 31', 1905.

' 5 SH-EETS-S HEET 1 wmmw: wuw/bo q No. 891,784. 'PATENTED JUNE 23,1908.

' s.s. sBY ERT.-

SINGLE PHASE .GO MMUTATOR MOTOR. A LIOA'TION' FILED JAN. 31. 1905.

QSHEETS-SHEET 2.

PATENTED JUNE 23, 1908.

sfs. SEYPERT. SINGLE {FHA-SB GOMMUTATORMOTOR.

APPLICATION .FILED JAN. 31. 1905. m

' 6 SHEETS-SHEET a.

No. 891,784. I -PATENTED JUNE 23, 1908.

' S. S. SEYF ERT.

SINGLE PHASE GOMMUTATOR MOTOR.

APPLICATION FILED JAN. 31, 1905.

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No. 891,784. P'A'IENIED JUNE 23, 1908.

s. s. SBYFERT. SINGLE PHASE GOMMUTATOR MOTOR.

APPLIGA'ILI O N FILED. JAN. 31 1905.

' w 6 SHEETS-SHEET 5 wmwtoz UNITED STATES PATENT GFFIOE.

STANLEY s. SEYFERT, oEsoU'rH BETHLEHEM, PENNSYLVANIA, ASSIGNOR orONE-BALE TO WILLIAM s. FRANKLIN, or SOUTH BETHLEHEM, PENNSYEVANIA.

' 'smGLE-rHnsE COMMUTATOR-MOTOR.

-- Specification of Letters Patent? I Patented June 23, 1908.

- I Application filed Ianuaryfl, 1905. Serial No. 213,483.

To all-whom it may concern:

Be it known that I, STANLEY S. SEYEERT, ofSouth Bethlehem, in the countyof North ampton, and in. the State'of Pennsylvania, have invented acertain new and useful Imrovement in Single Phase Commutatorl otors',and do hereby declare that the following is a full, clear, and exactdescription thereof, .reference being had to the accom-' panyingdrawings, in which n Figures 1 and 2 are diagrams illustrating therelations between voltage and current in a single phase motor, underdifferent conditions; Figs. 3 and 4 are, respectively, transverse and.longitudinal sectional viewsof a motor embodyingmy invention; Fig. 5 isa diagrammatic view of the connections of my motor when used asillustrated in Figs. 1 to 4; Fig. 6 ,is a diagrammatic view of theconnections of my motor when used as a repulsion motor; and Fig. 7 is anelevation of that form of my invention in which the internal field isstationary, and the external armature revolves. 5 1

The object of my invention has beento provide a single phase commutatormotor ,of high eiiiciency, lightweight, and small size, and to suchends, my invention-econsists, in the single phase commutator motorhereinafter specified;

Single-phase motors have heretofore been subject to several very seriousdisadvantages, as compared to the direct-current motor. First, theirpower factor is low, owing td cause of this inductance, the currentfalls 'far behind the electromotive force of supply in This is due tothe fact that lower "flux' densities are employed in the iron of thealternat-' ing current motor than in-the direct current 7 motor toreduce the core losses; As more iron must be employed. in thealternating than in the direct current=-motor,'and, as the m gcoactingtherewi the comparatively great inductance of they field andarmature coils of the motor. Be-

space on an electric car ywhich can-'be def voted to a motor is limited.by height of the floor, the horse-power of an alternating current motorof the types prior to mine for such purposes, have been limited ascompared wit the direct current motor. It will, therefore, be seen that,to reduce the size and Weight of the alternating current motor withoutimpairing its power rating and efiiciency is very desirable. i In theseries motor for alternating currents, when the machine is running, acertain 01- tiorrjof the electromotive force of supp y is used inovercoming the impedance of the field; another portion in overcomingthat of the armature, while the remainder balances the counterelectromotive force induced in the armature by rotation. This isillustrated in Fig. 1, in which, when the motor is starting tromotiveforce,if t bythevector 0 A; the voltage. lost through inductahce of thefield coils by O B; the volcoils by O C; then the line O D representsthe total voltageconsumed by the field. If, now, a short-circuitedwinding be placed on the field member so as to act as a shortcircuitedSecondary with the armature coils as primary,'the inductance of thearmature due to leakage offlux, be" counteracted. Such short-circuitedsecondary isv termed .a compensating windingil, and the armature 'th'istermed a compensated iif errin still. to Fig; 1,-' the lineEFgepresen'tsxthe volta e lost in the and there is, conseguently, nocounter elece currentbe represented tage lost through the resistance ofthe 'fi eld" can, with the exception of the smallamount armaturedue't'othe leakage in uctance only, and-the line'l) E representsthat'lost through resistance; of" the armature.

by the armature at starting, and OF repre- The line D F then representsthe total voltage consumed.

sents the total starting voltage of the motor. 7

The oounter electromotiveforce which is introducedin the armature whenthe motor isrunning, is represented by the line E G. If the currentbeunchanged, the field voltage will remain .the same, and the line 0 Hwillre resent the running volta e. I The lineG H 'Wll representi thevoltage 0st in armature,

due to leakage reactance. It will be observed that as the line E'Frepresents loss of voltage, due to leakage inductance at starting, andas the line GH represents that when running, the latter is smaller thanthe (strengthening the armature involving former, because thealternations of the current in the armature decrease in frequency, asthe motor speed increases.

Let cosine. @represent the power factor at the given speed of rotation.In order to make the power factor as large as ossible, the angle Q mustbe reduced as muc as possible. This may be done, as will be seen by Fig.1, (1) by decreasing the inductance of the field coils; or (2) bydecreasing the armature inductance. The armature inductance, havingalready been reduced by the compensating windings, is very small inamount, and, therefore, improvement must take the direction of reducingthe field inductance.

Since the power of the motor is proportional to the product of the fieldstrength by the armature ampere turns, one way to better the powerfactor, cosine Q of the motor, is to weaken the field (so as to get lessinductive drop) and strengthen the armature no disadvantage since itsinduction may be compensated). With a certain diameter of rotatingarmature, as universally used in these motors, the only way to increasethe armature ampere turns is to deepen the slots in the armature core,but, asthe slots approach each other as'they are extended toward thecenter of the core (the slots lying in a radial direction) they cannotbe materially deep-- ened beyond present practice, Without their beingrun together and cutting off the teeth formed between them. Therefore,it is impracticable to increase the armature ampere turns by deepeningthe slots on the single phase motors heretofore used.

The third way in which the power factor cosine Q can be increased is byincreasing the counter-electromotive force. The inducedcounter-electromotive force is the most important element in determiningthe power actor of the motor when running, since such electromotiveforce is always in phase with the current, and the power factor would beunity if such counter-electromotive force were the only one acting. Thegreater this counterelectromotive force is, as compared with theelectromotive force lost by inductance, the better the power factor ofthe motor. Therefore, it will be seen that, as

. above stated, the power factor can be increased by increasing theinduced counter- This may be done either (1 by strengthening the field;or .(2) by increasing the number of turns on the armature. The firstmethod is impracticable, becauses trengthening the field would increasethe inductive drop in the l" :ld correspondso that nothing would begained. The second method; namely, strengthening the armature, isunobjectionable, since the armature may be compensated and the increasedinductance counteracted. This method is, however, impracticable exceptto a limited extent with alternating current motors as constructedprevious to mine, because, as has been stated, it can only be done withan armature of a given size by deepening the slots in the armature core,and that would result in cutting off the teeth between the slots.

In Fig. 2 are illustrated the voltages for a motor in which the fieldcoils have been weakened, while the armature has been strengthened, andthe increased value of cosine -Q is evident. The line 0 H represents therunning voltage when the counterelectromotive force has been increasedthe amount represented b the line G G In the case of an alternatingcurrent motor, then, a weak field is desired, as compared to thearmature. This is diametrically the opposite of what is desired in adirect current motor, where a strong field and a weak armature arerequired, so as to avoid armature reaction as much as ossible.

So far as I am aware, sing e phase alternating current motors of thedirect current type have all been built with internal armatures andstationary external fields. All compensated alternating current motors,previous to mine, so far'as I am aware have been built with internalarmatures. I have found that the power factor of a single-phasealternating-current motor can be very advantageofily increased bychanging the relative posit-ions of thel'field and'armature, making thefield the rotating member, and the armature the stationary member,withother necessary alterations, whereby a remarkable increase ofefficiency, Without increase in weight, can be obtained. The changing ofthe relative positions of field and armature in the alternating currentcommutating motor produces advantages which belong solely to this class.of motor.

In carrying my invention into practice, I provide, as illustrated inFigs. 3 and 4, a stationary armature core I, consisting preferably ofsheet-metal disks or laminations. The disks are secured to the casing K,as by dove-tail slots 'i which engage dove-tails k on the casin Thecasing is provided with openings through which heat may radiate from thearmature core. The armature core is dprovided with notches i which areadapte to receive the armature bars L. As the notches i radiate outwardfrom their entrances, it is evident that the teeth between the notchesincrease in cross-section, lnstead of decreasing in cross-section 1n thedirection toward the'bottom of said slots, so

that the flux density in such teeth is nowhere greater than at theirends. A shaft M is mounted in bearings in the casing and carries arotating field N.

In Fig. 3 the upper half of the field is shown in cross-sectlon, whilethe lower half is shown in elevation. The field preferably laminated inthe usual way, and is provided -T correspond to the brush leads, Whilethe theresis'tance.

with the Bars. are setv in notches in the field core and are. providedwith connections R tofform compensating windings for counteracting theinductance of the armature. Current-is communicated to the motor andtaken from it through brushes S which, respectively, bear upon collectorrings T (there being four rings and brushes in the case of a repulsionmotor, and two in the case of a series motor.) The colis carried by theshaft, and they have connections V with brush holders W -that aremounted upon the shaft-M and rotate with the field, carrying brushes X.In the instance chosen for illustration, two of the rings other twocorrespond to the field terminals. The brushes rotate Within an internalcommutator consisting of bars Y which are clamped between plates Zbybolts A. The

commutator bars" are connected with the armature coils by means whosetheory will not be explained in the present case, since they are thesubject of anotherapplication, filed by me February 20th, 1905, SerialNo. 246,587 .and the object of-which is to overcome the objectionablesparking under the brushes at the face of the commutator.

In Fig. 5 the windings are an posed to be connected in series, and thereore but two rings T of each set are supplied with brushes, the remainingtwo rings of each set being connected together by a bridgcpiece N. The

large ring K, divided as a commutator, represents the commutator of anarmature. The coil L within thelarge ring represents the field. Theconcentric rings -,M at the center of theEdiagram represent thecollector rings T, and the twoconcentric rings Orep resent the source ofsupply. w

In Fig. 6, the connections.areillustrated when the machine is operatedas a repulsion motor, each of the four'rings T, represented in thediagram by the rings M, being supplied with a brush; The conventions ofthis diagram are the same as those illustratedin Fig. 5, and it will benoted that the bridge piece N is omitted; the source of, supply 0 isconnected to the brushes which bear u on the rings Mconnectedwithfthe'field,.w e the rings M to which .the commutatorbrushes are connected,,'are connected with a resistance P, sothatacircuit of the a1 inature through the brushes is closed through Theadvantages in a single-phase commutator motor arising from the'placingof the field inside the armatureare numerous and fundamental. The fieldcore can be made as smallas desired and canhave as small .a core as maybe wished.- The depth of ture teeth, (since the slots extend fartherthat 'the flux density in the air away from each other the deeper theyare.

ternal field, in spite of the fact wthatv the output is greater. Thismeans a slower speed motor, and, therefore, a smaller gear ratio andgreater gear efficiency. Because of the greater amount of spaceavailable for armature slots, the armature ampere turns may be largelyincreased for the same size and weight of motor, by making the armatureexternal. The tangential magnetic drag on the rotor is thus increased inthe same ratio (the field flux being the same in each case), and thetorque is greater both on this account and on account of the greaterdiameter of the rotor which is permitted. v

Because of the increase in armature ampere turns made possible by thenew arrangement, the counter-electromotive force of the armature becomescom aratively greater, and

4 is ob- .while that of the fieldmaybe c orrespondingly decreased,without altering the power ductance may be compensated, this means abetter ower factor or the motor. By ma ing the field internal, theleakage of field flux is less, and hence a lower induc-- tive componentof the field voltage 'results,

, and. a better power factor is obtained. This is due, first, to thefact that, with the internal field, diverging poles are obtained;

.whereas, with the external field, conver ing poles areobtained; andsecond, to'the Tact ga is a great deal lower with ,the internal fieldthan with the external field. When it is considered that the leaka eflux is a large proportion of the total fie d flux, the effect on theinductance of the field coil can be..seen.

With the internal: field, the ratio of armature. ampere turns to fieldam ere turns maybe i ncreased to almost any d dsired amount, because thearmature is free and unrestricted in its dimensions.;'. that is, the,slots can be made of any: desired depth, without thinning the teeth, theteeth,-in fact, growing thicker with the greater dc th of slot With theinterna field there is greater ease in getting the necessary area forslots for compensating winding, because the field poles of the motor,but, since the armature incan have a greater peripheral width for thesame size and weight of motor.

The compensating turns can be a great deal shorter with the internalfield than with the external field, and hence, for the same amount ofcopper a better compensation is obtained with the internal field. Thisis true, first, because the turns may be given greater sectional area(being shorter) for the same amount of copper; and, second, becausetheir resistance is less on account of their shorter length, and hencethe flux necessary to induce the compensating currents is greatlyreduced,

which means better compensation and better power factor.

In my motor there is very much more room than usual for resistance leadsand choking devices of, any sort thatmay be used to make possiblesatisfactory commutation. This room The armature iron, which is the seatof the .variable iron loss, is increased in volume in the case of theinternal field, but the average totaliron loss for different speeds isnot greater with the internal field than with the external field. Thearmature, being external, is best suited for radiating heat".

It is obvious that various changes can be made in the above illustratedconstruction, which will be within the scope of my invention. Forinstance, the armature may rotate while the field is held stationary,the armature being external to the field as before described. This formof my invention is illustrated in Fig. 7. In such figure the motor ismounted on a stationary shaft H. This shaft has fixed to it the internalstationary field I. The external rotating armature K turns on the shaftand is provided with a gear wheel L, by which power can be taken fromthe motor. Current is supplied from the alternator M to brushes N and O,the latter contacting with slip rings P and Q1 res ectively. These sliprings are connected with brushes R and S respectively, which rotate withthe field, and the brushes complete the circuit with the armaturethrough slip rings T and I U on the armature.

Having thus described my invention, what I claim is 1. An alternatingcurrent commutator In spite of the higher motor, comprising thecombination of an external armature, a commutator therefor, and aninternal uncommutated field.

2. In an alternating current commutator motor, the combination of anexternal menuber, a commutator connected thereto and stationary withrespect thereto, and an internal uncommutated member.

8. In an alternating current commutator motor, the combination of anexternal stationary member, a commutator connected thereto, andstationary with respect thereto, an internal rotating uncommutatedmember, and a source of alternating current.

4. The combination with a source of alternating current and a deviceconsisting of internal and external relatively rotatable members, acommutator. attached to the external member and brushes attached to theinternal member, both members in the normal use of the device beingincontinuous circuit with said source of current, said parts being soconnected'that the magnetic poles of the armature shall rotate relativethereto.

5. The combination of a source of alternating current and a deviceconsisting of an internal uncommutated member and an external eommutatedmember, both members in the normal use of the device being in continuouscircuit with said source of current,

said parts being so connected that the ma netic poles of the commutatedmember shall rotate relative thereto, the sole function of saidcombination being the conversion of, electrical into mechanical energy.

6. The combination ofa source of alternating current and a deviceconsisting of an internal and an external member, said ex ternal memberhaving a continuous coil, or. series of coils, a commutator having eachbar separately connected with said continuous 0011 or series of coils,both said external and internal member in the normal use of the devicebeing in continuous circuit with said source of current, said partsbeing so connected that the magnetic poles of the armature shall rotaterelative thereto.

7 The. combination with an alternating circuit, ofa motor comprising twoelements, one external to the other, said elements being. relativelyrotatable, said elements being connected to said circuit, means forcommuand external mutually inductive elesome;

the external element, said parts being so connected that the magneticpoles ofthe armature shall rotate relative thereto.

,9. A motor consistin of'the combination l o rneans on said internalelement for compenfsatingthe' nductance on said external ele-- ment,said parts being so connected that the magnetic poles of the armatureshall rotate relativethereto.

'10. The combination'with a source of al ternating current, of-a motorconsisting of .in-.

ternal and external mutuallyinductive elements, relatively rotatable, acommutator connected with-said external element, and

v means on said internal element for compensating the inductance of saidexternal element, said parts being so connected that the magneticpolesof the armature shall rotate relative thereto. 11. In an alternatingcurrent commdtator motor, the combination of an internal compensatingmember, an external compensated member, commutating connection betweensaid members, and means for supplying alternating current to saidcompensated member, said parts bein so connected that the magnetic )olesof t e armature shall'rotate relative t ereto. 12. In an alternatingcurrent commutator motor, the combination of an internal compensatingmember, an external compensated member, a commutating connection betweensaid members, and means for supplying alternating current to saidcompensated member, the ampere turns of the external member beingrelatively large in pro ortion to those of the internal member, saiparts being so connected that the magnetic poles of the armature shallrotate relative thereto. 4 13. The combination with an alternatincurrent circuit, of a motor comprising a fiel and a commutatedarmatureof large inductance external to said field, said armature andfield being connected to said circuit, and means for compensating theinductance of the armature.

14. A motor comprising the combination of a field and a commutatedarmature of large inductance external to said field, said armature andfield being connected tosaid circuit, and means for compensating theinductance of said armature, said parts being so connected that themagnetic poles of the armature shall rotate relative thereto.

60 15. In an alternating current commutator motor, the combination of anexternal arma ture, an internal field, means for compensating theinductance of the armature, a com mutator connected to such armature,and

5 brushes carried by thefield, said parts being so connected that themagnetic poles of the armature shall rotate relative thereto.

16. In an alternating current commutator motor, the combination of astationary external armatureda rotary-internal field, a 7 commutatorconnected to such armature, rotary brushes connected to said field, andmeans for compensating the inductance of the armature,said parts beingso connected t hat the magnetic poles of the armature shall rotaterelative thereto;

17. The combination with a source of aljternating current,-of a motorconsisting of an external armature, an internal field, both connectedwithsaid source of alternating curg0 rent, there bein a commutatorconnected to said armature, rushes carried by said field, and means forcompensating the inductance of said armature, sald parts being soconnected that the magnetic poles of the armature shall rotate relativethereto.

18. The combination with a source of alternatingv current, of a motorconsisting of an external armature, an internal field, both connectedwith said source of alternating current, acommutator connected to saidarmature, and brushes carried by said field, said armature and saidcommutator being stationary, said brushes being rotary, an

,means for compensating the inductance'of said armature, said partsbeing so connected that the magnetic poles of the armature shall rotaterelative thereto. a 1

19. In an alternating current commutator motor, the combination ofastationary external armature, a rotary internal field, a stationarycommutator connected to said armature, and having an internal contactsurface for the brushes, rotary brushes connected to said field andadapted to make contact with said surface, and means for compensatingthe inductance of said armature, said parts being so connected that themagnetic poles of the armature shall rotate relative thereto.

20. In an alternating current commutator motor, the combination of astationary armature, a rotary internal field, means for compensating theinductance of said armature, a stationary commutator connected to saidarmature, rotary brushes for said commutator, said brushes beingconnected to said field, collector rings' connected 'to' said field, andstationary brushes contacting with said collector rings, and adapted tobe connected with a source of current, said parts being so con-I nectedthat the magnetic poles of the armature shall rotate relative thereto.21, The combination with a source of alternating current, of a motorconsisting of-a stationary external armature, a rotary internal field,said armature and field being connected with said source of alternatingcurrent,a stationary commutator connected to said armature, and havingan internal contact surface for the brushes, rotary 1 brushes connectedwith said field, and adapted to make contact With said surface, andmeans for compensating the inductance of the armature, said arts beingso connected that the magnetic poles of the armature shall rotaterelative thereto.

22. The combination with a source of alternating current, of a motorconsisting of a stationary external armature, a rotary internal field,said field and armature being both connected with said source ofalternating current, a stationary commutator connected to said armature,rotary brushes for said commutator, said brushes being connected to saidfield, said field being provided with collecting rings, stationarybrushes contacting with said collecting rings and adapted to beconnected with said source of current, and means for compensating theinductance of said armature, said parts being so connected that themagnetic poles of the armature shall rotate relative thereto.

23. In an alternating current commutator motor, the combination with anexternal armature and a commutator therefor, of an internal field memberhaving diverging poles, and means for compensating the inductance of thearmature.

24. In an alternating current commutator motor, the combination with astationary external armature and a commutator therefor, of an internalrotar T field member having diverging poles, and means for compensatingthe inductance of the armature.

25. The combination with a source of alternating current, and of amotor, said motor consisting of an external commutated armature, aninternal field member having diverging poles, said armature and fieldboth being connected with said source of alternating current, and means.for compensating the inductance of the armature.

26. The combination with a source of alternating current, of a motorconsisting of an external commutated armature, a core provnjled with0011 slots radiating outward from its inner surface, an internal fieldmember, both of said members being connected with said source ofalternating current, and

means for compensating the inductance of said armature.

27. In an alternating current commutator motor, the combination of anexternal armature having a core provided with coil-slots radiatingoutward from itsflkiner surface, a

to rotate relative to the armature.

and means for compensating the inductance I of the armature.

29. The combination with a source of alternating current, of a motorconsisting of an external stationary armature having a core providedwith slots radiating outward from its inner surface, an internal rotaryfield member, and compensating winding for said armature, said windingbeing located on said field member.

, 30. In an alternating current commutator motor, the combination withan external armature, of an internal field member having poles and alsohaving conductors situated in the poles, and so connected as tocompensate or annul the inductance of the armature, and a commutator forcausing the magnetic poles of the armature to rotate relative to thearmature.

31. In an alternating current commutator conductors situated in thepoles and so connected as to compensate or annul the inductance of thearmature, and a commutator for causing the magnetic, poles of thearmature to rotate relative td the armature.

32. In a dynamo electric machine, the combination with an externalarmature, of an internal field member, compensating connections for saidarmature, said connections consisting of bars mountedin slots in thecore of said field membei and substantially parallel to the axisthereof, the corresponding bars on opposite sides of the'poles beingconnected together, and a commutator for causing the magnetic poles oftlpe armature In testimony that I claim the foregoing I have hereuntoset my hand.

STANLEY S. SEYFERT.

' Witnesses:

EDWIN J. PRINDLE, KATHERINE E. LAWLOR.

